This invention relates to a switching device using a so-called rubber switch, and more particularly to a rotatable dial mechanism used as a select switch incorporating a rubber switch.
Cameras and like equipment incorporating electronic circuits are provided with different kinds of switches. Recently, rubber switches have been increasingly used to satisfy the requirement for more compactness and thinness of such equipment.
FIG. 13 shows one example of such rubber switches. The rubber switch 11 is made by molding rubber or a similar resilient material and has a pair of projections 13 that are pressed by an operating member (not shown). The top inner surface of the projections 13 are integrally provided with contacts 12 opposite to conductors 14a of a substrate 14. The contacts 12 are held out of contact with the conductors 14a of the substrate 14 due to the resilience of the projections 13. The rubber switch 11 is thus electrically turned on through engagement of one contact 12 with the conductor 14a of the substrate 14 by alternatively depressing the projections 13 with the operating member. Releasing the operating member from the projections 13 then returns the switch to the initial non-contact position.
Also, there is a switch mechanism with the rubber switch 11 as mentioned above wherein a pair of projections 13 are alternatively pressed, which has conventionally been provided with means for restoring the neutral or off (on) position, but this results in a complicated structure. For a switch mechanism without any rubber switch, it has been necessary to provide the operating member itself with switching contacts in addition to incorporating the means restoring the neutral or off (on) position. This has again made such a switch mechanism complicated in construction.
Also known is a rotatably operable dial mechanism used as a momentary switch to operate the aforementioned rubber switch. The momentary switch turns a motor forward and backward in dependence on the direction of rotation of a rotatable dial. It returns to the neutral position with release of the operating force. In recent electronic cameras, different modes of camera operation as well as manual shutter speeds are often selected by complex operation of two different switches. In this case, one of the two switches may be a rotatable dial mechanism (select switch) rotatably movable between the neutral, right and left operative positions.
Such a rotatable dial mechanism achieves its primary function basically with a finger seating part provided on the rotatable dial. However, it has been difficult to produce such a rotatable dial which is stable when a finger is seated but does not turn the dial, while at the same time ensuring ease of rotational operation. In case of blind operation, it has sometimes caused operational mistakes and dislocation of the dial itself.